Microsoft Word C045543e doc Reference number ISO 11545 2009(E) © ISO 2009 INTERNATIONAL STANDARD ISO 11545 Third edition 2009 11 15 Agricultural irrigation equipment — Centre pivot and moving lateral[.]
INTERNATIONAL STANDARD ISO 11545 Third edition 2009-11-15 `,,```,,,,````-`-`,,`,,`,`,,` - Agricultural irrigation equipment — Centre-pivot and moving lateral irrigation machines with sprayer or sprinkler nozzles — Determination of uniformity of water distribution Matériel agricole d'irrigation — Pivots et rampes frontales équipés de buses d'arrosage ou d'asperseurs — Détermination de l'uniformité de la distribution d'eau Reference number ISO 11545:2009(E) Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 Not for Resale ISO 11545:2009(E) PDF disclaimer This PDF file may contain embedded typefaces In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy The ISO Central Secretariat accepts no liability in this area Adobe is a trademark of Adobe Systems Incorporated Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing Every care has been taken to ensure that the file is suitable for use by ISO member bodies In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below `,,```,,,,````-`-`,,`,,`,`,,` - COPYRIGHT PROTECTED DOCUMENT © ISO 2009 All rights reserved Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester ISO copyright office Case postale 56 • CH-1211 Geneva 20 Tel + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyright@iso.org Web www.iso.org Published in Switzerland ii Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 – All rights reserved Not for Resale ISO 11545:2009(E) Contents Page Foreword iv Scope Terms and definitions 3.1 3.2 3.3 3.4 Test conditions and equipment Collectors .2 Wind Evaporation Elevation .4 Test procedures Calculations Evaluation .6 Reporting of test results .7 Annex A (normative) Sample data sheets and test report forms for required information 10 Bibliography 16 `,,```,,,,````-`-`,,`,,`,`,,` - iii © ISO 2009 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11545:2009(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work of preparing International Standards is normally carried out through ISO technical committees Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part The main task of technical committees is to prepare International Standards Draft International Standards adopted by the technical committees are circulated to the member bodies for voting Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights ISO shall not be held responsible for identifying any or all such patent rights ISO 11545 was prepared by Technical Committee ISO/TC 23, Tractors and machinery for agriculture and forestry, Subcommittee SC 18, Irrigation and drainage equipment and systems This third edition cancels and replaces the second edition (ISO 11545:2001), which has been technically revised iv `,,```,,,,````-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 – All rights reserved Not for Resale INTERNATIONAL STANDARD ISO 11545:2009(E) Agricultural irrigation equipment — Centre-pivot and moving lateral irrigation machines with sprayer or sprinkler nozzles — Determination of uniformity of water distribution Scope This International Standard specifies an in-field method for determining the uniformity of water distribution in the field from centre-pivot and moving lateral irrigation machines equipped with sprayer or sprinkler nozzles The calculation of the coefficient of uniformity is also specified This International Standard is applicable to agricultural irrigation machines for which the water application device is more than 1,5 m above the soil surface and for which the water distribution from successive devices overlaps `,,```,,,,````-`-`,,`,,`,`,,` - It is not applicable to the evaluation of centre-pivot irrigation machines equipped with various corner arm application devices Terms and definitions For the purposes of this document, the following terms and definitions apply 2.1 centre-pivot irrigation machine automated irrigation machine consisting of a number of self-propelled towers supporting a pipeline rotating around a pivot point and through which water supplied at the pivot point flows radially outward for distribution by sprayers or sprinklers located along the pipeline 2.2 moving lateral irrigation machine automated irrigation machine consisting of a number of self-propelled towers supporting a pipeline transverse to the direction of travel moving in such a way that the pipeline remains generally in a straight line, traversing the field in a straight path, and through which water supplied to the irrigation machine at any point along the pipeline is distributed over a basically rectangular area by sprayers or sprinklers located along the pipeline 2.3 sprinkler water-distribution device of a variety of sizes and types EXAMPLE Impact sprinkler, fixed nozzle sprinkler, irrigation gun 2.4 irrigation sprayer device that discharges water in the form of fine jets or in a fan shape without rotational movement of its parts 2.5 sprinkler package collection of water-distribution devices fitted to the outlets of either centre-pivot or moving lateral irrigation machines, either with or without moving components, piping, pressure or flow-control devices and supporting plumbing designed for a specific irrigation machine and set of operating parameters © ISO 2009 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11545:2009(E) 2.6 endgun set of one or more sprayers or sprinklers installed on the distal end(s) of a centre-pivot or moving lateral irrigation machine to increase the irrigated area, and usually operating for only a portion of the time to conform to field boundaries 2.7 test pressure pressure of a centre-pivot or moving lateral irrigation machine measured at the first available outlet downstream from the elbow or the tee at the top of the inlet to the pipeline 2.8 effective radius radius of the circular-field area to be irrigated by a centre-pivot irrigation machine, measured as the distance from the pivot point to the terminal sprayer or sprinkler on the pipeline 2.9 effective length dimension parallel to the pipeline of a moving lateral machine, measured as the distance between the two most distant end sprayers or sprinklers on the pipeline, except where a portion of the area under the pipeline is used for the water supply system and not for crop production, in which case that distance is excluded 2.10 wetted radius rw distance measured from the centreline of a sprayer or sprinkler to the last collector with measurable water or estimated from the manufacturer's catalogue data as half of the diameter of coverage 2.11 applied depth di adjusted volume of water caught in each collector in an array of collectors plus the average amount of water that evaporates while the water is in the collector, divided by the area of the collector opening `,,```,,,,````-`-`,,`,,`,`,,` - 2.12 collector receptacle into which the water is deposited during a water distribution test 2.13 client person(s) or organization for which a test is performed 2.14 tester person(s) or organization that conduct(s) a test 3.1 Test conditions and equipment Collectors 3.1.1 All collectors used for a test shall be identical and shaped such that water does not splash in or out The lip of the collector shall be symmetric and without depressions The height of each collector shall be at least twice the maximum depth of the water collected during the test, but not less than 150 mm It shall have a circular opening with sharp edges free from deformities The diameter shall be at least half the height, but shall not be less than 85 mm To minimize measurement error, it is recommended that testers use collectors that are as large as practicable Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 – All rights reserved Not for Resale ISO 11545:2009(E) 3.1.2 Place the collectors uniformly along two or more straight lines perpendicular to the direction of travel of the machine The maximum collector spacing within each line shall be in accordance with Table Collectors shall not be located where the sprayer or sprinkler pattern is affected by the tower structural components Table — Maximum spacing for collectors Sprayer or sprinkler wetted radius m Maximum collector spacing m < 10 W 10 To minimize systematic errors, collectors of adjacent lines should be offset The offset should be 1/nth the collector spacing, where n is the number of collector lines (see Figures and for collector layout detail) Ensure that the distance between the collectors is not a multiple of the distance between the sprayers or sprinklers Collectors should be moved to avoid wheel tracks Record the location of the collectors 3.1.3 Place the lines of the collectors so that the distance between the lines is as follows For centre-pivot irrigation machines, locate the collectors along two or more lines extending radially from the pivot point Ensure that the distance between distal ends of the radial lines is no more than 50 m Record the spacing pattern (see Figure 1) For moving lateral irrigation machines, locate the collectors along two or more lines parallel to the pipeline Ensure that the lines of the collectors extend across the effective length of the machine and are not more than 50 m apart Record the spacing pattern (see Figure 2) 3.1.4 Locate the collectors so that obstructions, such as the crop canopy, not interfere with the measurement of water application When an obstruction is higher than the elevation of the collector, but below the water-distribution device height, maintain a horizontal unobstructed distance of at least twice the height of the obstruction on both sides of the collector rows (see Figure 3, case A) For systems with water-distribution devices that operate below the crop canopy height, maintain a horizontal unobstructed distance of at least 1,25 times the wetted radius of the sprayer or sprinkler on each side of the collector rows (see Figure 3, case B) 3.1.5 The entrance portion of the collectors shall be level When wind velocities during the test are expected to exceed m/s, the entrance of the collectors should be no more than 0,3 m above ground or crop canopy The discharge height of the sprayer or sprinkler shall be at least m above the top of the collector Record the height of the sprayer or sprinkler nozzles and the entrance to the collectors 3.2 3.2.1 Wind Measure the wind velocity during the test period with a rotating anemometer or equivalent device 3.2.2 Determine the wind direction, relative to the line of collectors, with a vane indicating at least eight points of the compass 3.2.3 Locate the equipment for measuring wind velocity at a height of m and within 200 m of the test site, in a location representative of the wind conditions at the test site 3.2.4 Ensure that the anemometer has a threshold velocity not exceeding 0,3 m/s and is capable of measuring the actual velocity to within ± 10 % 3.2.5 The accuracy of the test procedure begins to decrease when the wind velocity exceeds m/s The test should not be used as a valid measure of the uniformity or performance of a sprinkler package if the wind velocity exceeds m/s To test at wind velocities greater than m/s, the client and tester should understand © ISO 2009 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS `,,```,,,,````-`-`,,`,,`,`,,` - Not for Resale ISO 11545:2009(E) the limitations of the test results Measure and record the wind velocity and the direction prevailing at the beginning and end of the test and during the test at intervals not longer than 15 3.3 Evaporation 3.3.1 The test should be conducted during periods that minimize the effect of evaporation, such as at night or during early daylight hours 3.3.2 To minimize the effect of evaporation from collectors during the test, measure and record the volume of water in each collector as soon as possible after the collector is no longer within the range of the water pattern To adjust the volume caught in each collector for evaporation loss, estimate the time during which each collector contains water, i.e from the time the collector is first within the range of the water pattern until the collector volume is measured 3.3.3 To account for evaporation from the collectors, place a minimum of three control collectors containing the anticipated catch at the test site Record the volume of water in each collector before and after the test and record the time of day each collector was put in place and when it was recorded after the test Calculate the mean evaporation rate from the control collectors (Ei) (for reporting, see A.1) The dimensions of the control collectors shall be identical to the collectors specified in 3.1.1 Locate the control collectors where the microclimate is essentially unaffected by the operation of the machine This is normally upwind from the test area 3.3.4 Employ appropriate procedures for minimizing evaporation These include the use of evaporation suppressants or specially designed collectors Record the methods used to suppress evaporation, including, if applicable, the type of suppressant 3.4 Elevation Conduct the test in an area having elevation differences that are within the design specifications of the sprinkler package Measure elevation differences with an instrument capable of measuring an elevation change of ± 0,2 m over a distance of 50 m Include a sketch of the ground surface profile along each line of collectors with the test results, unless the ground surface is level Test procedures 4.1 Before testing an irrigation machine, verify that the sprinkler package has been installed according to the design specifications, unless otherwise specified by the client 4.2 Adjust and maintain the pressure of the water supplied to the irrigation machine during the test to within ± % of a test pressure mutually agreed upon by client and tester Ensure that the pressure measurement device is capable of accurate measurement to within ± % of the test pressure Record the test pressure 4.3 Operate the irrigation machine at a speed that will deliver an average depth of application of not less than 15 mm, unless otherwise specified by the client 4.4 Record the application depth data by measuring the volume or, alternatively, the mass or depth of water collected in the collectors Adjust for evaporation as follows: adjusted catch volume (Vi) equals catch volume recorded in each collector (Vci) plus the average amount of water evaporated from the control collectors during the time (ti) water was in the specific collector (for reporting, see A.2) Ensure that the measurement device is accurate to within ± % of the average amount of water collected 4.5 Eliminate any obviously incorrect data points caused by occurrences such as leakage, tipped collectors or other explainable variances from the water distribution analysis Ensure that the number of eliminated observations does not exceed % of the total number of depth measurements Report all observations Record the number of eliminated observations, together with the reasons for their elimination `,,```,,,,````-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 – All rights reserved Not for Resale ISO 11545:2009(E) 4.6 Eliminate from the analysis those observations beyond the effective radius or effective length of the irrigation machine 4.7 If the sprinkler package is designed with an endgun, perform the test with the endgun operating in the same operational mode as used for designing the sprinkler package The number of sprayers or sprinklers should remain constant during the test If desired, the test may also be performed with the endgun not in operation in order to evaluate the water distribution for those conditions 4.8 The data from up to 20 % of the collectors on the inner portion of the total length of a centre-pivot irrigation machine can be eliminated from the water distribution analysis if mutually agreed upon by the tester and the client Collectors need not be placed in the inner portion of the centre-pivot irrigation machine if the intent of the test is to determine the water distribution with the inner portion of the centre-pivot irrigation machine excluded from the analysis Calculations 5.1 Calculate the coefficient of uniformity for a centre-pivot irrigation machine using the modified formula of Heermann and Hein [1] Additional performance parameters may be used to characterize the water distribution uniformity The tester shall clearly identify any such additional parameters, including the calculation formula The modified formula of Heermann and Hein is: C uH ⎡ ⎢ ⎢ = 100 ⎢1 − ⎢ ⎢ ⎣ ⎤ n ∑ V i − V w S i ⎥⎥ i =1 n ∑ (V i S i ) i =1 ⎥ ⎥ ⎥ ⎦ `,,```,,,,````-`-`,,`,,`,`,,` - where CuH is the Heermann and Hein coefficient of uniformity; n is the number of collectors used in the data analysis; i is a number assigned to identify a particular collector, normally beginning with the collector located nearest the pivot point (i = 1) and ending with i = n for the collector furthest from the pivot point; Vi is the volume (or, alternatively, the mass or depth) of water collected in the ith collector; Si is the distance of the ith collector from the pivot point; V w is the weighted average volume (or, alternatively, the mass or depth) of water collected, computed as: n Vw = ∑ Vi S i i =1 n ∑ Si i =1 5.2 Calculate the coefficient of uniformity for a moving lateral irrigation machine using the Christiansen [2] formula Additional performance parameters may be used to characterize the water distribution uniformity The tester shall clearly identify any such additional parameters, including the calculation formula © ISO 2009 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11545:2009(E) The Christiansen formula is: CuC ⎡ ⎢ ⎢ = 100 ⎢1 − ⎢ ⎢ ⎣ ⎤ n ∑ Vi − V ⎥⎥ i =1 n ∑ Vi i =1 ⎥ ⎥ ⎥ ⎦ where CuC is the Christiansen coefficient of uniformity; n is the number of collectors used in the data analysis; Vi is the volume (or, alternatively, the mass or depth) of water collected in the ith collector; V is the arithmetic average of the volume (or, alternatively, the mass or depth) of water collected by all collectors used in the data analysis, computed as: n ∑ Vi V = i =1 n 5.3 Calculate CuH or CuC, whichever is appropriate, for each line of collectors Calculate a combined coefficient of uniformity, CuH or CuC, using the data from all lines of collectors 5.4 If an irrigation machine with an endgun is tested, use the procedure given in 4.7 to measure the coefficient of uniformity when the endgun is on, and, optionally, when it is off To characterize the operation of the endgun, record (see A.1) the approximate area of the field irrigated while the endgun is operating and the approximate area irrigated while the endgun is turned off 5.5 Prepare a graph showing the volume (or, alternatively, the mass or depth) of water collected in each collector, plotted against the distance from the pivot point or along the lateral, together with the positions of the towers and sprayers or sprinklers Plot the data from each line of collectors separately Evaluation 6.1 The calculated coefficient of uniformity shall be used as an indicator of sprinkler package performance with respect to the field, environment, pressure conditions and pressure variations prevailing during the test The coefficient of uniformity of a new sprinkler package can be used for the comparison of different types of sprinkler packages and as a reference for similar irrigation machines that have been used for a period of time 6.2 If the coefficient of uniformity for an installed irrigation machine deviates substantially from the value specified in the initial design, conduct other investigations to determine the cause A coefficient of uniformity smaller than the design value may indicate worn, broken or malfunctioning water-application devices 6.3 The graph of the depth applied along the lateral can help identify problems in the operation of an irrigation machine Locations along the lateral where the depth applied is 10 % higher or lower than the average depth should be investigated to determine the cause of the variation `,,```,,,,````-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 – All rights reserved Not for Resale ISO 11545:2009(E) Reporting of test results Record the data measured for this test on forms similar to the standard data presentation forms given in A.1 and A.2, and the test summary form shown in A.3 Document and explain special arrangements between the client and the tester Justify data inconsistencies on the data forms Include with the test results additional data not required by this International Standard if that data will help characterize uniformity of water distribution `,,```,,,,````-`-`,,`,,`,`,,` - Dimensions in metres Key wheel tracks centre-pivot lateral pivot point offset ith collector of jth line (staggered from other line) collector spacing NOTE lines The collector offset is approximately equal to 1/nth the collector spacing, where n is the number of collector a Reference point for Si (distance of ith collector from the pivot point) b Maximum spacing for collectors: m for rw < 10 m; m for rw W 10 m Figure — Collector layout for determining water distribution of centre-pivot irrigation machines © ISO 2009 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11545:2009(E) Dimensions in metres Key wheel tracks moving lateral arbitrary reference position for distance offset ith collector of jth line collector spacing NOTE lines a The collector offset is approximately equal to 1/nth the collector spacing, where n is the number of collector Maximum spacing for collectors: m for rw < 10 m; m for rw W 10 m Figure — Collector layout for determining water distribution of moving lateral irrigation machines `,,```,,,,````-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 – All rights reserved Not for Resale ISO 11545:2009(E) Case B: water-distribution device below crop canopy (l W 1,25 rw) Case A: water-distribution device above crop canopy (l W h) Key pipeline water-distribution device obstruction (crop) collector rw h wetted radius height of obstruction Figure — Guidelines for placement of collectors with obstructions (e.g crops) during testing `,,```,,,,````-`-`,,`,,`,`,,` - © ISO 2009 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11545:2009(E) Annex A (normative) Sample data sheets and test report forms for required information A.1 Field and machine data sheet Test identification: Location of test: Machine description Manufacturer/model: Number of towers: Distance between pivot and end tower: m Lateral length segment 1: m segment 2: m segment 3: m segment 2: m segment 3: m Diameter of lateral pipe segment 1: m Type of sprinkler package: Pressure regulators: Yes No Location of pressure regulators: refer to attached drawing Pressure rating of pressure regulator: refer to attached drawing Endgun: approximate area irrigated with — endgun off: — endgun on: Nominal height of nozzle or distribution plate above ground: m Height of top of collector above ground: m Operating conditions Test pressure: kPa Machine speed — elapsed time of test: h — distance end tower travelled: m — centre-pivot end tower: m/h — moving lateral: m/h — timer setting: % — timer cycle duration (time on+off): s `,,```,,,,````-`-`,,`,,`,`,,` - 10 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 – All rights reserved Not for Resale ISO 11545:2009(E) Evaporation calculation from control collectors Collector No Initial volume Time of day collector place Final volume Time of day collector recorded Volume lost Time collector contained water Evaporation rate ml h ml h ml h ml/h Mean evaporation rate, Ei `,,```,,,,````-`-`,,`,,`,`,,` - Field Layout Show lateral location during test Wind information Plot wind vector for each wind measurement NOTE Each concentric circle is equivalent to m/s, with the outside circle equal to 10 m/s Agreed maximum wind velocity for test: m/s Mean wind velocity during test: m/s 11 © ISO 2009 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11545:2009(E) Lateral elevation: `,,```,,,,````-`-`,,`,,`,`,,` - Plot the approximate relative field elevation of the lateral during the test on the graph Key X Y distance along lateral, m difference in field elevation, m a Entrance b End A.2 Sample data sheet to record test results Test identification: Collector line number: Diameter of collectors (Dc): mm Area of collector opening [Ac = 0,785(Dc)2]: mm2 Nominal spacing of collectors: m Nominal spacing between collector lines: m Offset: m Mean evaporation rate from control collectors (Ei): ml/h 12 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 – All rights reserved Not for Resale ISO 11545:2009(E) Catch volume Adjusted catch volumec Applied depthd Product of distance and volumee ti Vci Vi di SiVi h ml ml mm Time Time of Collector Indication Distance Estimated collector day No for of time of collector contained eliminated collector day water volume from collector dataa measured first pivotb within range of water pattern i Si m h h ∑ Si a Mark if data eliminated (see 4.5) b Ignore this column for moving lateral systems ∑ Vi ∑ S iVi c Vi = Vci + Eiti d di = 000 Vi/Ac e The product of distance and volume is used only for calculating the coefficient of uniformity for centre-pivots 13 © ISO 2009 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS `,,```,,,,````-`-`,,`,,`,`,,` - The adjusted volume equals the volume collected in each collector plus the average amount of water evaporated from the control collectors during the time (ti) water was in the specific collector, i.e.: Not for Resale ISO 11545:2009(E) A.3 Test summary sheet Test identification: Wetted radius of terminal sprayer or sprinkler (2.10): m Centre-pivot Distance from pivot point to terminal sprayer or sprinkler: m Effective radius (2.8): m Moving lateral Distance between the two most distant sprayers or sprinklers: m Distance under pipeline used for water supply: m Effective length (2.9): m Number of collectors installed: Number of collectors used in analysis (n): Percentage of collectors omitted from analysis: % Reason(s) for exclusion: `,,```,,,,````-`-`,,`,,`,`,,` - 14 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2009 – All rights reserved Not for Resale ISO 11545:2009(E) Weighted Averages Collector Line Total or combined = _ _ _ _ = _ _ _ _ = _ _ _ _ ⎥ = _ ⎥ ⎥ ⎦ _ _ _ = _ _ _ _ = _ _ _ _ a) Centre-pivot Sum of volume (mass or depth) and distance product ∑ Vi S i Sum of distances ∑ Si n i =1 n i =1 n Weighted average volume (mass or depth) Vw = ∑ Vi S i i =1 n ∑ Si i =1 Coefficient of uniformity C uH ⎡ ⎢ ⎢ = 100 ⎢1 − ⎢ ⎢ ⎣ ⎤ n ∑ Vi − V w S i ⎥⎥ i =1 n ∑ (Vi S i ) i =1 b) Moving lateral n Average volume (mass or depth) V = Coefficient of uniformity C uC ∑ Vi i =1 n ⎡ ⎢ ⎢ = 100 ⎢1 − ⎢ ⎢ ⎣ ⎤ n ∑ Vi − V ⎥⎥ i =1 n ∑ Vi i =1 ⎥ ⎥ ⎥ ⎦ `,,```,,,,````-`-`,,`,,`,`,,` - 15 © ISO for 2009 – All rights reserved Copyright International Organization Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11545:2009(E) Bibliography HEERMANN, D.F and HEIN, P.R Performance characteristics of self-propelled center pivot sprinkler irrigation systems Transactions of the ASAE, 1968, 11, No 1, pp 11-15 [2] CHRISTIANSEN, J.E Irrigation by Sprinkling Bulletin 670, 1942 University of California, College of Agriculture, Agricultural Experiment Station, Berkeley, California [3] American Society of Agricultural Engineers Standard ASAE S436, Test Procedure for Determining the Uniformity of Water Distribution of Center Pivot and Lateral Move Irrigation Machines Equipped with Spray or Sprinkler Nozzles 16 © ISO 2009 – All rights reserved `,,```,,,,````-`-`,,`,,`,`,,` - [1] Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale